In recent years, compact, wearable image display apparatuses that can be worn on the head or on eyeglasses have been proposed. For example, in one such known image display apparatus, image light of an image displayed on a small image display device secured to the temporal region is guided by a transparent light-guiding member to a position in front of the eye to display the image as an expanded virtual image in an observer's field of view (for example, see JP 2007-286317 A (PTL 1)). The small, lightweight light-guiding member does not greatly block the field of view, and the entire image display apparatus can be made small and lightweight, allowing use as a wearable device that can continually be worn on the body and used.
By reducing the light-guiding member in size, however, stray light and ghost light that are reflected at locations such as the inner surfaces of the light-guiding member tend to become pronounced. In particular, as the cross-sectional size of the light-guiding member is smaller, ghost light reflected at the sides of the light-guiding member is visible closer to the display image in the field of view. Therefore, in PTL 1, grooves are formed at different positions on two opposing sides of the transparent substrate at which image light is reflected, and unnecessary reflected light within the transparent substrate for light guiding is reflected and removed.